Improvement in variable cut-offs for direct-acting engines



a Sheets-Sheet 1.

B. BRAZELLE. VARIABLE CUT-OFFS FOR DIRECT-ACTING ENGINES. No.183,4:46.

Patented 0ct.17,18"76;

Wz'f/ws 5 es y 2.22% W "PETERS, PHOTO-UTHOGRAPHER, WASHINGTON, D C

s Sh eets -Sheet s.

B. BRAZELLE.

IBM 22W f m'fiwsse s: Jaye/27232:

Zen kmz'w 2: 7 :5

N. PETERS, PNOTU-LITHDGRAPHER. WASHINGYON- D rrnn STATES ENT BENJAMINBRAZELLE, OF ST. LOUIS, MISSOURI.

Specification forming part of Letters Patent No. 183,446, dated October17, 1876 application filed January 26, 1876.

To all whom it may concern:

Be it known that I, BENJAMIN BRAZELLE, of St. Louis, Missouri, haveinvented an Improved Variable Out-Off Steam-Engine, of

which the following is a specification:

The improved features of this invention relate, first, in arrangingwithin an auxiliary cylinder double stop-pistons, and the manner inwhich same are operated to control the slide-valve to establishwide-open induction and exhaust ports from the beginning to the end ofcylinder-piston stroke, thereby admitting steam to act upon saidcylinder-piston at full boiler-pressure, also avoiding back pressure;secondly, to the further arrangement of double carrier-pistons, and tothe manner in which same are operated to control the slidevalve to cutoff steam at any desired pointof the piston-stroke, thereby utilizingthe full expansive steam-power; thirdly, to the novel arrangement ofinlet and exhaust steam pas sages, ports, and chambers, by which thesteam-power shall operate the stop and carrier pistons at required timesto cut off steam, as well as impart the required reciprocation tocylinder-piston; fourthly, to an improved construction of a rotary ordisk valve for controlling the inlet to and exhaust from the pistons inauxiliary cylinder; fifthly, to an improved construction of a disk-coveror admission-plate, to control and regulate the admission of steam tothe disk-valve and stop and carrier pistons; sixthly, to the combinationof the disk-valve, also disk-cover, with relation to the steam-chest ofthe auxiliary cylinder, and its contained pistons; lastly, to certaindetail construction of parts, all of which will now more fully appear.

Of the drawing, Sheet 1, Figure 1 is a longitudinal sectional elevation.Fig. 2 is'a side elevation, with cut-oft parts removed, showingvalve-seat in the top cylinder, and its arrangement of high-pressure andcut-off ports and passages. Sheet 2--Fig. 3 is a top sectional plan.Fig. 4 is a transverse sectional elevation. Sheet 3--Fig. 5 is aperspective of rotary or disk valve. Fig. 6 is a perspective ofdisk-cover and the head of the top cylinder steam-chest. Figs. 7, 8, 9,and 10 are, respectively, sectional details, showing the portcommunications to admit and exhaust steam to and from the top cylinders,to operate the carrier-pistons as well as the outer stop pistons.

valve.

' A is the engine-cylinder. This has the usual steam-ports a a, whichserve alternately as inductive and exhaust ports.

tioned communicate with the valve-seat B of a steam-chest, B, in whichoperates an ordinary slide-valve, b. (See Figs. 1 and 4..)

steam-chest B. der steam-chest 0, having the valve-seat 0 as shown inFigs. 2 and 4.. The inlet of steam to the steam-chest is by means of theinlet-port c, and 0 representing the exhaustpassage leading from thesteam-chest C out of main exhaust. (See Figs. 2 and 4.)

From the valve-seat G the steam-ports 0 c? 0 c communicate to theinterior of the top cylinder 0, Fig. 2, as follows: 0 0 the highpressureports, have their passages, as shown in dotted lines, Figs. 2 and 3, tocommunicate with each opposite interior end of the cylinder 0 thecut-off ports 0 0 have their passages to communicate withthe cylinder 0,as shown also in Figs. 2 and 3. Further, it will be noticed that thearrangement of all these ports is such that the high-pressure port 0 isover the cut-off port 0 on one side, while the high-pressure port 0 isunder the'cut-off port c on the opposite side, of the valve-seat and asshown in Fig. 2.

I call the ports 0 c high-pressure ports because their passages lead tothe outer or stop pistons, to actuate thereby admission and exhaust ofsteam to reverse the stroke of the main piston, and the ports 0" ccut-oft ports because they admit and exhaust steam alternately, and, assuch, control the opera tions of the cut-off or carrier-pistons. Thesaid arrangement of these ports just mentioned enables me to control theoperations of the respective pistons, to achieve their independentfunctions of cutting off the steam, and changing the action or travel ofthe main piston at the end of every stroke thereof.

The pistons contained in the top cylinder are the carrier-pistons D I)and the stoppistons D D (See Figs. 1 and 3.)

Fig. 11 is a face view of my rotary- A is the main exhaust. The ports orpassages just men- 0 isan auxiliary cylinder, which .forms part of theSaid cylinder has the cylin- Ilhe carrier-pistons D D 'I construct ofthe plicatei character shown in Figs. Land 3,

:ir outer piston-faces, in distance, being orter than the distance apartof thecut-off rts c 0 and so that the stroke or travel of id pistonsshall be the relative distance reired to causesame to move theslide-valve 0 lap the induction-port, to ,cut 011' further mission ofsteam through said port to main linder. The hollow spaces either side ofa piston-heads serve to permit the steam to ualize the movements of saidpistons. The nular groove d shown in the center of the Trier-pistonsreceives the slotted leg of the.

ile-valve I), (see Figs. 1 and 3,) said valve ing, by universalcoupling, secured to its b. Lastly, the carrier-pistons'havepassgthrough their center the stem d that unites astop-pistons D DThese pistons are also the duplicate character shown in Figs. 1 d 3; butat 61 each piston is made smaller circumference to create asteam-chamber 'steam to enter and exhaust by means of zcut-off ports 0 0The travel orstroke the stop-pistons D D is also relatively.

:h as to actuate the slide-valve b to cover a ports of the main cylinderalternately, 1 when the change of its piston-stroke ocrs. Within thecylinder steam-chest I pro- (See Figs. 5 and 11.) These inlet-ports lpositioned in a circle near the periphery of l valve, while theexhaust-ports are in a aller circle; also, each alternate exhaust- 't isdiametrically in line with each inlett. (See Figs. 5 and 11.)

it can be here stated that the exhaust-ports further related in pairs,so as to establish \aust communication with main exhaust, such pairs,when the valve is rotating to ileft, are e e or e e c 6 and when saidvalve 'eversed the pairs to exhaust are e e or c 4 e Examining all theports, as viewed the outer face of the valve, theFig. 11 resents theirposition and arrangement. viewed from the inner face of the valve, 3Fig. 5,) it will be seen that the exhaust- 'ts e e c further communicatewith cored .mbers f f f respectively, while the re-' ining exhaust-portsc e 8 each communies with a center cored chamber, f Likee theinlet-ports communicate with cored .mbers f f f respectively, thechambers l f being separated from the center chamj by the walls f andthe chambersf f blSO separate from f by the walls f and, ;ly, theexhaust-chambers are separate from inlet-chambers by the walls f --a1lshown ig. 5. The chambers f f are elongated a Fig. 5) inorder toestablish communical as soon as possible with the-slide-valve, tctuatethis to cover a port of its main cylinder; also, the exhaust-chambersf ff are The disk-valve E has an arbor, Ei, (see Figs.

4., 5,) by. means whereof it. is connected to main shaft of the engineto derive its rotation.

In operative connection with the rotary valve E, I provide a disk plateor cover to control and regulate the admission of steam into inlet-portsof the said valve E, as this rotates, as well as to establish exhaustconnection between the pairs ofexhaust-ports, and by means whereof thepistons in top cylinder operate the slide-valve to cut off steam at anypoint, as well as establish the reverse operation of the engine-piston.G is therefore this disk plate or cover. Its construction is indicatedin Fig. 6, having its opposite margin sides cut away to form inlet-steamspaces g g,'

leaving however its full margin faces at g g.

The cut spaces g 9 enable me to cut off steam earlier or later,according to the varia= ble points of cut-off desired, and the fullfaces g g are to prevent the admission of steam until the proper time ofcut-off has arrived;

Further, I provide in the face of the cover G" (contiguousto the valve)exhaust-chambers g 1 These chambers unite the exhaust-ports in pairs, asalluded to, to permit a free exhaust, the. blank faceof said covercovering such exhaust-ports in the valve notacting as such. Thedisk-cover G has also forming part of it a sleeve, G, (see Fig.4=,) sothat it can be turned on the arbor of the valve. i

The operative relationship of the disk-cover G and the rotary valve E,so as to admit and exhaust steam in and from the top cylinder to operatethe double pistons, is more fully illus-' trated in Figs. 7, 8, 9,10.Thefollowing is i the description of said parts-first, however,

to produce the result of cutting ofl' steam,say at one-eighth of mainpiston-stroke: Suppos 'ing the valve on its seat, the cover seated nextto said valve, and in position so that its steam-space 9 will admitsteam as soon as said ,valve hastbeen turned to uncover its inlet port ethen steam will enter same, pass along its cored chamber f and into thecut-ofi port 0, (see Fig. 7,) and operate the carrier-pistons D D to oneside, which cuts off steam by means of the slide-valve b cove'ring'theinduc-f tion-port of the main cylinder. At the same time the exhaustistaking place opposite the pistons D D through the cut-off port 0 intoexhaust port and chamber 6 f of the valve E, thence into exhaust-port'eof same, and

finally out of main exhaust. (See Fig. 8.) Thus thesteam is admitted topass into and exhaust from the auxiliary cylinder, and 0p erate thecutoff pistons at the point of cut-off mentioned, and 1311682111118manner of establish? ing inlet and exhaust communications to saidpistons takes place, no matter at. what frac tional point of the strokethe cut-off is desired;

The next operation of parts to be noticed is the manner in which thesteam is admitted to andexha'usts from the-faces of the stop pistonsD-.D?. For this' purpose I refer now to Figs. 9 and 10. Theadmission-cover Gr being I in' the same position as shown in Figs.'7 andI 8, steam will be admitted through its open space g, and as the valve Euncovers the in-;' let-port e the steam, entering its chamber f passes,into the high-pressure port 0 to the; outer face of one of thestop-pistons D D operating both to one side ,and thus-changes, by meansof the slide-valve'b, the entrance of steam to main cylinder to reversethe stroke. of its piston. At the same time the exhaust from theopposite side of the stop-pistons takes place through the high-pressureport 0 into exhaust port and chamber 0 f thence into chamber g of thecover, returning by way of exhaust 6 into center exhaust, and

out of main exhaust. (See Fig. 10.) Thus the reverse operation of thestop-pistons is effected.

The disk-cover G, by its sleeve G, is placed on the arbor of thedisk-valve. Engaging the sleeve of the cover is the head H, which closessteam-tight the steam-chest G (See Figs. 6, 4, and 3.) The head H has astop, h, (see Fig. 6,) which limits the movement of the cover Graccording to the requirements of the points of cut-off, which I indicateon the periphery of said cylinder-head. Thus, as shown in Fig. 3, thevariable points of cut-off are one-eighth, one-fourth, three-eighths,one-half, to seven-eighths.

It represents an indicator, (see Figs. 3 and 4,) which is set todetermine the point of cutoff. It is secured to the sleeve of thediskcover by a nut, k (See Figs. 3, 4.) It is by simply moving theindexto the fraction indicated on the head E that changes the relativeposition'of the disk-cover Gr, to allow steam to enter earlier or later,according to the set point of cut-off.

The connection of the disk-valve E to derive its rotary motion is madeto the engine-- V shaft in any suitable way; but said motion of thevalve should be in the ratio of one to every three revolutions of saidshaft, since there are three inlet and six exhaust ports. The arm of theindicator, in cases of stationary engines, can also be attached to thegovernor for the same purpose of controlling the cut-off.

The complete operation of my variable cutofi is as follows: Say that theindicator has been set at one-half the stroke of the enginepiston. Thissets the disk-cover G at the required point to prevent inlet of steam tothe valve E until the main piston has made its half-stroke. Arriving atthis point, the rotary valve uncovers an inlet-port to the steam, which,entering a cut-off port of the top cylinder, actuates thecarrier-pistons D D to one side, causing the slide-valve b to cover theinduction-port leading to the main cylinder, and allowing steam to actexpansively, the exhaust from the opposite side of thecut-ofl' pistonsjust spoken of taking place at same time out of centerexhaust.- ltshould be here particularly noticed that while the foregoing operationtakes place the eduction-port from the opposite end of main cylinder isopen, allow'.-. ing free exhaust from same to take place, and giving methe advantage of an open exhaust during theentire stroke, andpreventingback pressure on the piston from steam or confined air. Assoon as the piston has completed its stroke the admission of steam toand from the auxiliary cylinder to operate its stop-pistons will takeplace, so that said stop-pistons, by means of the slide-valve, willuncover the opposite engine-port for the new stroke of its piston. Afull open exhaust-port at the commencement of the stroke, and before theinduction is open, is thus had, which gives ample time for the steam toescape; also, an instantaneous and full open induction-port isthus'obtained at the beginning of the stroke, which enables me toutilize full boiler-pressure.

Throughout its complete operation my variable cut-off admits, exhausts,and cuts off steam at any point of the stroke desired, and that with theuse of a single slide-valve.

What I claim is- 1. The piston made in two partsviz., heads D D and D D-the latter set having stem d passing through the former set, whenapplied and operating within an auxiliary cylinder, as

and for the purpose set forth.

2. The cut-ofl' pistons D D auxiliary cylinder 0, having steam-chest Oand ports 0 c c 0 in combination with slide-valve b and main ports of asteam-cylinder, to cut off steam from the latter, as and for the purposeset forth.

3. Within the auxiliary cylinder 0, the stoppistons D D and thesteam-chest (3 having the ports 0 c 0 0 in combination with slidevalve12 and the main ports of a cylinder,whereby the piston of the latter isoperated in the manner and for the purpose herein set forth.

4. The combination of the double piston D D D D carrying slide-valve b,auxiliary cylinder 6, and steam-chest B, as and for the purpose setforth.

5. The relative arrangement of the inletports 0 0 e having'ooredchambers f f f also exhaust-ports e 6 e e e e and cored chambers f f ff, in a rotary disk-valve E, in combination with steam-chest 0 havingports and passages c c c c c 0 and by means whereof the admission andexhaust of steam are had, in the manner and for the purpose set forth. v

6. The rotary valve E, having inlet-ports e 0 e cored chambers f f fexhaust-ports e e e e e' veflcored chambers ff f f in combination withthe high-pressure ports 0 cylinder O, and its stop-pistons D D', tooperate as and for the purpose set forth..

7. The rotary valve E, having inlet-ports e e 6 cored chambers f f fexhaust-ports e e e e 6 e cored chambers f f f f in combination withcut-ofl' ports 0 c cylinder 0, and its carrier-piston D D to operate asand for the purpose set forth.

g 9 full faces y g, exhaust chambers g 9 in combination with a rotaryvalve, E, having inlet ports and chambers e e e f f f, and exhaust portsand chambers e 0 e e e" 6 and f f f f to operate as described. y

In testimony of said invention I have hereunto set my hand.

BENJAMIN- BRAZELLE.

Witnesses:

WILLIAM W. HERTHEL, CHAS. F. MEISNER.

